Driving circuit of thin-film transistor electroluminescent display and the operation method thereof

Abstract

A circuit for driving an organic light-emitting diode (OLED) in a thinfilm transistor electroluminescent (TFT-EL) display at least includes the first and the second transistors. Wherein, a data line and a capacitor are respectively connected to the source and drain electrodes of the first transistor. The capacitor is charged from the data line by turning on the first transistor. And, the capacitor and an OLED are respectively connected to the source and drain electrodes of the second transistor. The capacitor is discharged by turning on the second transistor, and results in light emitting of the OLED.

What is claimed is:  
     
       1. A circuit for driving a light-emitting diode (LED) in a thin-film transistor electroluminescent (TFT-EL) display, comprising: 
       a data line;  
       a scan line;  
       a discharge line;  
       a capacitor;  
       a light-emitting diode;  
       a first transistor having a first gate electrode, a first source electrode, and a first drain electrode, wherein the first gate electrode is connected to the scan line, the first source electrode is connected to the data line, and the first drain electrode is connected to the capacitor; and  
       a second transistor having a second gate electrode, a second source electrode, and a second drain electrode, wherein the second gate electrode is connected to the discharge line, the second source electrode is connected to the capacitor and the second drain electrode is connected to the light-emitting diode.  
     
     
       2. The circuit according to  claim 1 , wherein said first transistor is switched on and the second transistor is turned off, when said data line charges said capacitor through said first transistor. 
     
     
       3. The circuit according to  claim 1 , wherein said LED is driven by said capacitor through said second transistor. 
     
     
       4. A method for driving a light-emitting diode (LED) in a thin-film transistor electroluminescent (TFT-EL) display, comprising: 
       inputting a scan signal for switching on a first transistor;  
       charging a capacitor by a data signal from a data line through said first transistor;  
       switching off said first transistor by discontinuing said scan signal, after said charging step is completed;  
       inputting a discharge signal for switching on a second transistor; and  
       driving said LED by discharging said capacitor through said second transistor.  
     
     
       5. The method according to  claim 4 , wherein said scan signal is input from a scan line of said TFT-EL display and is applied on a gate of said first transistor. 
     
     
       6. The method according to  claim 4 , wherein said discharge signal is input from a discharge line of said TFT-EL display and is applied on a gate of said second transistor. 
     
     
       7. The method according to  claim 4 , wherein said second transistor is switched on and said first transistor is switched off when said LED is driven by the capacitor. 
     
     
       8. The method according to  claim 4 , wherein said second transistor is switched off and said first transistor is switched on during said charging step. 
     
     
       9. A circuit for driving a light-emitting diode (LED) in a thin-film transistor electroluminescent (TFT-EL) display, comprising: 
       a data line;  
       a scan line;  
       a discharge line;  
       a capacitor;  
       a light-emitting diode;  
       a first transistor having a first gate electrode, a first source electrode, and a first drain electrode, wherein the first gate electrode is connected to the scan line, and the first source electrode is connected to the data line, and the first drain electrode is connected to the capacitor; and  
       a second transistor having a second gate electrode, a second source electrode, and a second drain electrode, wherein the second gate electrode is connected to the discharge line, and the second source electrode is connected to the capacitor, and the second drain electrode is connected to the light-emitting diode, said light-emitting diode being driven by a discharging current from said capacitor through said second transistor.  
     
     
       10. The circuit according to  claim 9 , wherein said first transistor is switched on and the second transistor is turned off, when said data line charges said capacitor through said first transistor.